AZGradientView.m

//
//  AZGradientView.m
//  AZAppearanceKitDemo
//
//  Created by Zachary Waldowski on 6/29/12.
//  Copyright (c) 2012 Alexsander Akers & Zachary Waldowski. All rights reserved.
//

#import "AZGradientView.h"
#import <QuartzCore/QuartzCore.h>

@interface AZGradientLayer : CALayer

@property (nonatomic) AZGradientViewType type;
@property (nonatomic) CGFloat angle;
@property (nonatomic) CGPoint relativeCenterPosition;
@property (nonatomic, strong) AZGradient *gradient;

@end

@implementation AZGradientLayer

@dynamic angle;
@dynamic gradient;
@dynamic relativeCenterPosition;
@dynamic type;

+ (BOOL) needsDisplayForKey: (NSString *) key
{
    if ([key isEqualToString:@"gradient"] || [key isEqualToString:@"type"] || [key isEqualToString:@"angle"] || [key isEqualToString:@"relativeCenterPosition"])
		return YES;
	else
		return [super needsDisplayForKey: key];
}

- (id <CAAction>) actionForKey: (NSString *) key
{
	if ([key isEqualToString: @"gradient"] || [key isEqualToString: @"type"])
	{
		CATransition *transition = [CATransition animation];
		transition.fillMode = kCAFillModeForwards;
		return transition;
	}
	else if ([key isEqualToString: @"angle"] || [key isEqualToString: @"relativeCenterPosition"])
	{
        CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath: key];
        animation.fromValue = [self.presentationLayer valueForKey: key];
        return animation;
    }
	
	return [super actionForKey: key];
}

- (void) drawInContext: (CGContextRef) context {
	[super drawInContext: context];
	
	UIGraphicsPushContext(context);
	{
		if (self.type == AZGradientViewTypeLinear)
			[self.gradient drawInRect: self.bounds angle: self.angle];
		else
			[self.gradient drawInRect: self.bounds relativeCenterPosition: self.relativeCenterPosition];
	}
	UIGraphicsPopContext();
}

@end

@implementation AZGradientView

- (AZGradientLayer *) gradientLayer
{
	return (AZGradientLayer *) self.layer;
}

+ (Class) layerClass
{
	return [AZGradientLayer class];
}

- (id) init
{
	if ((self = [super init]))
	{
		[self az_sharedInit];
	}
	
	return self;
}
- (id) initWithCoder: (NSCoder *) aDecoder
{
    if ((self = [super initWithCoder: aDecoder]))
	{
		[self az_sharedInit];
    }
	
    return self;
}
- (id) initWithFrame: (CGRect) frame
{
    if ((self = [super initWithFrame:frame])) {
		[self az_sharedInit];
    }
	
    return self;
}
- (id) initWithGradient: (AZGradient *) gradient
{
	if ((self = [super initWithFrame: CGRectZero]))
	{
		self.gradient = gradient;
		[self az_sharedInit];
	}
	
	return self;
}

- (void) az_sharedInit
{
	self.layer.shouldRasterize = YES;
	self.layer.rasterizationScale = self.layer.contentsScale = [[UIScreen mainScreen] scale];
}

#pragma mark - Gradient Accessors

- (AZGradient *) gradient
{
	return self.gradientLayer.gradient;
}

- (void) setGradient: (AZGradient *) gradient
{
	[self setGradient: gradient animated: NO];
}
- (void) setGradient: (AZGradient *) gradient animated: (BOOL) animated {
	[CATransaction begin];
	[CATransaction setAnimationDuration:animated ? (1./3.) : 0];
	[CATransaction setAnimationTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
	self.gradientLayer.gradient = gradient;
	[CATransaction commit];
}

#pragma mark - Gradient Type Accessors

- (AZGradientViewType) type
{
	return self.gradientLayer.type;
}

- (void) setType: (AZGradientViewType) type
{
	[self setType: type animated: NO];
}
- (void) setType: (AZGradientViewType) type animated: (BOOL) animated
{
	[CATransaction begin];
	[CATransaction setAnimationDuration:animated ? (1./3.) : 0];
	[CATransaction setAnimationTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
	self.gradientLayer.type = type;
	[CATransaction commit];
}

#pragma mark - Angle Accessors

- (CGFloat) angle
{
	return self.gradientLayer.angle;
}

- (void) setAngle: (CGFloat) angle
{
	[self setAngle: angle animated: NO];
}
- (void) setAngle: (CGFloat) angle animated: (BOOL) animated {
	[CATransaction begin];
	[CATransaction setAnimationDuration:animated ? (1./3.) : 0];
	[CATransaction setAnimationTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
	self.gradientLayer.angle = angle;
	[CATransaction commit];
}

#pragma mark - Relative Center Position Accessors

- (CGPoint) relativeCenterPosition
{
	return self.gradientLayer.relativeCenterPosition;
}

- (void) setRelativeCenterPosition: (CGPoint) relativeCenterPosition
{
	[self setRelativeCenterPosition: relativeCenterPosition animated: NO];
}
- (void) setRelativeCenterPosition: (CGPoint) relativeCenterPosition animated: (BOOL) animated
{
	[CATransaction begin];
	[CATransaction setAnimationDuration:animated ? (1./3.) : 0];
	[CATransaction setAnimationTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
	self.gradientLayer.relativeCenterPosition = relativeCenterPosition;
	[CATransaction commit];
}

@end